Nine years ago, as she lay on her death bed about to succumb to the breast cancer she’d been battling for five years, Marquischa Henderson Williams delivered a powerful and prophetic message to her son, then a 12-year-old boy.

“Quinnen, you’re going to be the one who takes care of everybody,’’ she told the second of her four children. “You’re going to be the one to make sure everybody is straight. I need you to do that.’’

Nine years later — specifically on Thursday night in Nashville, Tenn., where Quinnen Williams walked onto a stage, hugged NFL commissioner Roger Goodell and posed for a grip-and-grin photo while holding up a Jets jersey after he was drafted by the team with the third-overall pick — her son was making good on his mom’s last request.

As soon as he signs his first contract, Williams will be a millionaire with potential, based on his performance, to become a much more than than before his NFL career is over. He’s said the first thing he plans to do with his first paycheck is buy a car for his grandmother.

The music to Jets fans’ ears, though, was this: Quinnen Williams, sounding hungry and humble, insisted that this is only the beginning for him.

Still on stage in the immediate aftermath of the Jets drafting him, Williams was asked by ESPN’s Suzy Kolber what his mom would think.

“That I did it,’’ Williams said.

“[But] it’s just the beginning,’’ he quickly added. “I’ve got a long road ahead and I know she’s proud of me, but she doesn’t want me to get complacent. She’ll want me to keep going, keep working hard and finish school and get my degree.’’

Marquischa Henderson Williams, just 37 when she died, never got to see her son dominate at Alabama, where he had eight sacks and 19.5 tackles for losses this past season, and she won’t get the chance to see him play in those fancy new Jets uniforms as a pro. But she’s been — and will remain — a constant presence inside the soul of Quinnen.

“I’ve thought about my mom every last minute, how I need to not get complacent, stay disciplined and stay humble,’’ Williams said later on a conference call with reporters at the Jets team facility. “Those are the things I always think when I think about my mom. Those are things my mom instilled in me, the things that drive me. I know she’d be very proud, for sure.’’

So, good for the Jets. They didn’t get cute Thursday night. They didn’t overthink things. They just went and got their man.Sometimes going chalk in the NFL draft makes the most sense. And the Jets, resisting temptation to trade back and accumulate more picks, went chalk with the No. 3-overall pick and wasted little time picking Williams — 6-foot-3 and 303 pounds of raw, powerful disruptive talent.

If everything works to plan, Williams will be getting up close and personal with Brady, whose Kryptonite always has been pressure up the middle.

Kentucky’s edge rusher Josh Allen was still on the board when the Jets made their pick, but it was Williams they wanted all along.He has cherub cheeks and braces on his teeth — football’s version of “Big Baby’’ — but don’t let that fool you into thinking he’s soft. Williams has potential to be terror on the inside.

Williams has a chance to help Leonard Williams become the player the Jets envisioned him to be when they made him the sixth-overall pick in the 2015 draft by drawing some double teams away from him.

“I know that I’m coming in and I’ll be a dominant player up front,’’ Williams said. “I can get after the passer and I can also stop the run.’’

His performance last season — playing in the best conference in college football — backs that up.

Two years ago, Williams was a backup as a redshirt freshman. Today, he’s the third player picked.

“I knew something like this was possible,’’ Williams said. “[But] not this fast. I’m enjoying every moment of it.’’

If only his mother, his most powerful influence, could be here to enjoy it with him.